Broadband communication systems (BCSs) have proliferated in many regions of the world to distribute increasing amounts of programming for informational or entertainment purposes as well as providing networked communication between users (e.g. for telephony and video conferencing) and access to other sources of information such as the Internet. Such systems, also referred to as cable systems, use frequencies which are also used for and allocated to over-the-air broadcasting and radio communications, some of which serve emergency and safety functions. Interference is ideally prevented by confining the signals carried by BCS systems through the use of shielded cable wiring. However, as a practical matter, cable shielding flaws can occur due to damage, deterioration or poor maintenance practices and allow BCS signals to leak into the environment or allow the reciprocal effect of allowing broadcast signals and ambient noise to enter the cable.
Detection of cable shielding flaws is generally achieved through detection of the signal carried by the cable transmission system that has leaked into the environment, essentially by being broadcast from the shielding flaw. Detection of a signal that has leaked or egressed from a cable flaw may be performed in two stages: first, by a receiver in a mobile vehicle driven in the general vicinity of installed cables that associates a received signal, authenticated as originating from the BCS, with a location of the mobile vehicle using a global positioning system (GPS) receiver which thus reports a general location of a shielding flaw and, second, by a hand-held instrument that can allow repair personnel to follow increasing signal strength to the exact location of the shielding flaw so that repairs and/or maintenance can be carried out. Nevertheless, authenticating a received signal as one originating from a BCS is an inherent difficulty in locating actual cable shielding flaws since reception of a possible egress signal must necessarily be done in the presence of other radio frequency communications and noise. As the volume of information carried by a given BCS has been required to increase, coding schemes and formats have been developed to carry increasing quantities of information and, for that reason, the signal coding scheme used in BCSs has become statistically less distinguishable from noise and other radio frequency signals.